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Linux 3.11-rc3
[cris-mirror.git] / net / xfrm / xfrm_replay.c
blob8dafe6d3c6e41ebd20e5d0347d4ab9b0e6326a34
1 /*
2 * xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
3 *
4 * Copyright (C) 2010 secunet Security Networks AG
5 * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21 #include <linux/export.h>
22 #include <net/xfrm.h>
23
24 u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
25 {
26 u32 seq, seq_hi, bottom;
27 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
28
29 if (!(x->props.flags & XFRM_STATE_ESN))
30 return 0;
31
32 seq = ntohl(net_seq);
33 seq_hi = replay_esn->seq_hi;
34 bottom = replay_esn->seq - replay_esn->replay_window + 1;
35
36 if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) {
37 /* A. same subspace */
38 if (unlikely(seq < bottom))
39 seq_hi++;
40 } else {
41 /* B. window spans two subspaces */
42 if (unlikely(seq >= bottom))
43 seq_hi--;
44 }
45
46 return seq_hi;
47 }
48
49 static void xfrm_replay_notify(struct xfrm_state *x, int event)
50 {
51 struct km_event c;
52 /* we send notify messages in case
53 * 1. we updated on of the sequence numbers, and the seqno difference
54 * is at least x->replay_maxdiff, in this case we also update the
55 * timeout of our timer function
56 * 2. if x->replay_maxage has elapsed since last update,
57 * and there were changes
58 *
59 * The state structure must be locked!
60 */
61
62 switch (event) {
63 case XFRM_REPLAY_UPDATE:
64 if (x->replay_maxdiff &&
65 (x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
66 (x->replay.oseq - x->preplay.oseq < x->replay_maxdiff)) {
67 if (x->xflags & XFRM_TIME_DEFER)
68 event = XFRM_REPLAY_TIMEOUT;
69 else
70 return;
71 }
72
73 break;
74
75 case XFRM_REPLAY_TIMEOUT:
76 if (memcmp(&x->replay, &x->preplay,
77 sizeof(struct xfrm_replay_state)) == 0) {
78 x->xflags |= XFRM_TIME_DEFER;
79 return;
80 }
81
82 break;
83 }
84
85 memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
86 c.event = XFRM_MSG_NEWAE;
87 c.data.aevent = event;
88 km_state_notify(x, &c);
89
90 if (x->replay_maxage &&
91 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
92 x->xflags &= ~XFRM_TIME_DEFER;
93 }
94
95 static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
96 {
97 int err = 0;
98 struct net *net = xs_net(x);
99
100 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
101 XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
102 if (unlikely(x->replay.oseq == 0)) {
103 x->replay.oseq--;
104 xfrm_audit_state_replay_overflow(x, skb);
105 err = -EOVERFLOW;
106
107 return err;
108 }
109 if (xfrm_aevent_is_on(net))
110 x->repl->notify(x, XFRM_REPLAY_UPDATE);
111 }
112
113 return err;
114 }
115
116 static int xfrm_replay_check(struct xfrm_state *x,
117 struct sk_buff *skb, __be32 net_seq)
118 {
119 u32 diff;
120 u32 seq = ntohl(net_seq);
121
122 if (!x->props.replay_window)
123 return 0;
124
125 if (unlikely(seq == 0))
126 goto err;
127
128 if (likely(seq > x->replay.seq))
129 return 0;
130
131 diff = x->replay.seq - seq;
132 if (diff >= min_t(unsigned int, x->props.replay_window,
133 sizeof(x->replay.bitmap) * 8)) {
134 x->stats.replay_window++;
135 goto err;
136 }
137
138 if (x->replay.bitmap & (1U << diff)) {
139 x->stats.replay++;
140 goto err;
141 }
142 return 0;
143
144 err:
145 xfrm_audit_state_replay(x, skb, net_seq);
146 return -EINVAL;
147 }
148
149 static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
150 {
151 u32 diff;
152 u32 seq = ntohl(net_seq);
153
154 if (!x->props.replay_window)
155 return;
156
157 if (seq > x->replay.seq) {
158 diff = seq - x->replay.seq;
159 if (diff < x->props.replay_window)
160 x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
161 else
162 x->replay.bitmap = 1;
163 x->replay.seq = seq;
164 } else {
165 diff = x->replay.seq - seq;
166 x->replay.bitmap |= (1U << diff);
167 }
168
169 if (xfrm_aevent_is_on(xs_net(x)))
170 x->repl->notify(x, XFRM_REPLAY_UPDATE);
171 }
172
173 static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
174 {
175 int err = 0;
176 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
177 struct net *net = xs_net(x);
178
179 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
180 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
181 if (unlikely(replay_esn->oseq == 0)) {
182 replay_esn->oseq--;
183 xfrm_audit_state_replay_overflow(x, skb);
184 err = -EOVERFLOW;
185
186 return err;
187 }
188 if (xfrm_aevent_is_on(net))
189 x->repl->notify(x, XFRM_REPLAY_UPDATE);
190 }
191
192 return err;
193 }
194
195 static int xfrm_replay_check_bmp(struct xfrm_state *x,
196 struct sk_buff *skb, __be32 net_seq)
197 {
198 unsigned int bitnr, nr;
199 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
200 u32 pos;
201 u32 seq = ntohl(net_seq);
202 u32 diff = replay_esn->seq - seq;
203
204 if (!replay_esn->replay_window)
205 return 0;
206
207 if (unlikely(seq == 0))
208 goto err;
209
210 if (likely(seq > replay_esn->seq))
211 return 0;
212
213 if (diff >= replay_esn->replay_window) {
214 x->stats.replay_window++;
215 goto err;
216 }
217
218 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
219
220 if (pos >= diff)
221 bitnr = (pos - diff) % replay_esn->replay_window;
222 else
223 bitnr = replay_esn->replay_window - (diff - pos);
224
225 nr = bitnr >> 5;
226 bitnr = bitnr & 0x1F;
227 if (replay_esn->bmp[nr] & (1U << bitnr))
228 goto err_replay;
229
230 return 0;
231
232 err_replay:
233 x->stats.replay++;
234 err:
235 xfrm_audit_state_replay(x, skb, net_seq);
236 return -EINVAL;
237 }
238
239 static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
240 {
241 unsigned int bitnr, nr, i;
242 u32 diff;
243 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
244 u32 seq = ntohl(net_seq);
245 u32 pos;
246
247 if (!replay_esn->replay_window)
248 return;
249
250 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
251
252 if (seq > replay_esn->seq) {
253 diff = seq - replay_esn->seq;
254
255 if (diff < replay_esn->replay_window) {
256 for (i = 1; i < diff; i++) {
257 bitnr = (pos + i) % replay_esn->replay_window;
258 nr = bitnr >> 5;
259 bitnr = bitnr & 0x1F;
260 replay_esn->bmp[nr] &= ~(1U << bitnr);
261 }
262 } else {
263 nr = (replay_esn->replay_window - 1) >> 5;
264 for (i = 0; i <= nr; i++)
265 replay_esn->bmp[i] = 0;
266 }
267
268 bitnr = (pos + diff) % replay_esn->replay_window;
269 replay_esn->seq = seq;
270 } else {
271 diff = replay_esn->seq - seq;
272
273 if (pos >= diff)
274 bitnr = (pos - diff) % replay_esn->replay_window;
275 else
276 bitnr = replay_esn->replay_window - (diff - pos);
277 }
278
279 nr = bitnr >> 5;
280 bitnr = bitnr & 0x1F;
281 replay_esn->bmp[nr] |= (1U << bitnr);
282
283 if (xfrm_aevent_is_on(xs_net(x)))
284 x->repl->notify(x, XFRM_REPLAY_UPDATE);
285 }
286
287 static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
288 {
289 struct km_event c;
290 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
291 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
292
293 /* we send notify messages in case
294 * 1. we updated on of the sequence numbers, and the seqno difference
295 * is at least x->replay_maxdiff, in this case we also update the
296 * timeout of our timer function
297 * 2. if x->replay_maxage has elapsed since last update,
298 * and there were changes
299 *
300 * The state structure must be locked!
301 */
302
303 switch (event) {
304 case XFRM_REPLAY_UPDATE:
305 if (x->replay_maxdiff &&
306 (replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
307 (replay_esn->oseq - preplay_esn->oseq < x->replay_maxdiff)) {
308 if (x->xflags & XFRM_TIME_DEFER)
309 event = XFRM_REPLAY_TIMEOUT;
310 else
311 return;
312 }
313
314 break;
315
316 case XFRM_REPLAY_TIMEOUT:
317 if (memcmp(x->replay_esn, x->preplay_esn,
318 xfrm_replay_state_esn_len(replay_esn)) == 0) {
319 x->xflags |= XFRM_TIME_DEFER;
320 return;
321 }
322
323 break;
324 }
325
326 memcpy(x->preplay_esn, x->replay_esn,
327 xfrm_replay_state_esn_len(replay_esn));
328 c.event = XFRM_MSG_NEWAE;
329 c.data.aevent = event;
330 km_state_notify(x, &c);
331
332 if (x->replay_maxage &&
333 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
334 x->xflags &= ~XFRM_TIME_DEFER;
335 }
336
337 static void xfrm_replay_notify_esn(struct xfrm_state *x, int event)
338 {
339 u32 seq_diff, oseq_diff;
340 struct km_event c;
341 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
342 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
343
344 /* we send notify messages in case
345 * 1. we updated on of the sequence numbers, and the seqno difference
346 * is at least x->replay_maxdiff, in this case we also update the
347 * timeout of our timer function
348 * 2. if x->replay_maxage has elapsed since last update,
349 * and there were changes
350 *
351 * The state structure must be locked!
352 */
353
354 switch (event) {
355 case XFRM_REPLAY_UPDATE:
356 if (!x->replay_maxdiff)
357 break;
358
359 if (replay_esn->seq_hi == preplay_esn->seq_hi)
360 seq_diff = replay_esn->seq - preplay_esn->seq;
361 else
362 seq_diff = ~preplay_esn->seq + replay_esn->seq + 1;
363
364 if (replay_esn->oseq_hi == preplay_esn->oseq_hi)
365 oseq_diff = replay_esn->oseq - preplay_esn->oseq;
366 else
367 oseq_diff = ~preplay_esn->oseq + replay_esn->oseq + 1;
368
369 if (seq_diff < x->replay_maxdiff &&
370 oseq_diff < x->replay_maxdiff) {
371
372 if (x->xflags & XFRM_TIME_DEFER)
373 event = XFRM_REPLAY_TIMEOUT;
374 else
375 return;
376 }
377
378 break;
379
380 case XFRM_REPLAY_TIMEOUT:
381 if (memcmp(x->replay_esn, x->preplay_esn,
382 xfrm_replay_state_esn_len(replay_esn)) == 0) {
383 x->xflags |= XFRM_TIME_DEFER;
384 return;
385 }
386
387 break;
388 }
389
390 memcpy(x->preplay_esn, x->replay_esn,
391 xfrm_replay_state_esn_len(replay_esn));
392 c.event = XFRM_MSG_NEWAE;
393 c.data.aevent = event;
394 km_state_notify(x, &c);
395
396 if (x->replay_maxage &&
397 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
398 x->xflags &= ~XFRM_TIME_DEFER;
399 }
400
401 static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
402 {
403 int err = 0;
404 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
405 struct net *net = xs_net(x);
406
407 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
408 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
409 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
410
411 if (unlikely(replay_esn->oseq == 0)) {
412 XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
413
414 if (replay_esn->oseq_hi == 0) {
415 replay_esn->oseq--;
416 replay_esn->oseq_hi--;
417 xfrm_audit_state_replay_overflow(x, skb);
418 err = -EOVERFLOW;
419
420 return err;
421 }
422 }
423 if (xfrm_aevent_is_on(net))
424 x->repl->notify(x, XFRM_REPLAY_UPDATE);
425 }
426
427 return err;
428 }
429
430 static int xfrm_replay_check_esn(struct xfrm_state *x,
431 struct sk_buff *skb, __be32 net_seq)
432 {
433 unsigned int bitnr, nr;
434 u32 diff;
435 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
436 u32 pos;
437 u32 seq = ntohl(net_seq);
438 u32 wsize = replay_esn->replay_window;
439 u32 top = replay_esn->seq;
440 u32 bottom = top - wsize + 1;
441
442 if (!wsize)
443 return 0;
444
445 if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
446 (replay_esn->seq < replay_esn->replay_window - 1)))
447 goto err;
448
449 diff = top - seq;
450
451 if (likely(top >= wsize - 1)) {
452 /* A. same subspace */
453 if (likely(seq > top) || seq < bottom)
454 return 0;
455 } else {
456 /* B. window spans two subspaces */
457 if (likely(seq > top && seq < bottom))
458 return 0;
459 if (seq >= bottom)
460 diff = ~seq + top + 1;
461 }
462
463 if (diff >= replay_esn->replay_window) {
464 x->stats.replay_window++;
465 goto err;
466 }
467
468 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
469
470 if (pos >= diff)
471 bitnr = (pos - diff) % replay_esn->replay_window;
472 else
473 bitnr = replay_esn->replay_window - (diff - pos);
474
475 nr = bitnr >> 5;
476 bitnr = bitnr & 0x1F;
477 if (replay_esn->bmp[nr] & (1U << bitnr))
478 goto err_replay;
479
480 return 0;
481
482 err_replay:
483 x->stats.replay++;
484 err:
485 xfrm_audit_state_replay(x, skb, net_seq);
486 return -EINVAL;
487 }
488
489 static int xfrm_replay_recheck_esn(struct xfrm_state *x,
490 struct sk_buff *skb, __be32 net_seq)
491 {
492 if (unlikely(XFRM_SKB_CB(skb)->seq.input.hi !=
493 htonl(xfrm_replay_seqhi(x, net_seq)))) {
494 x->stats.replay_window++;
495 return -EINVAL;
496 }
497
498 return xfrm_replay_check_esn(x, skb, net_seq);
499 }
500
501 static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
502 {
503 unsigned int bitnr, nr, i;
504 int wrap;
505 u32 diff, pos, seq, seq_hi;
506 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
507
508 if (!replay_esn->replay_window)
509 return;
510
511 seq = ntohl(net_seq);
512 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
513 seq_hi = xfrm_replay_seqhi(x, net_seq);
514 wrap = seq_hi - replay_esn->seq_hi;
515
516 if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
517 if (likely(!wrap))
518 diff = seq - replay_esn->seq;
519 else
520 diff = ~replay_esn->seq + seq + 1;
521
522 if (diff < replay_esn->replay_window) {
523 for (i = 1; i < diff; i++) {
524 bitnr = (pos + i) % replay_esn->replay_window;
525 nr = bitnr >> 5;
526 bitnr = bitnr & 0x1F;
527 replay_esn->bmp[nr] &= ~(1U << bitnr);
528 }
529 } else {
530 nr = (replay_esn->replay_window - 1) >> 5;
531 for (i = 0; i <= nr; i++)
532 replay_esn->bmp[i] = 0;
533 }
534
535 bitnr = (pos + diff) % replay_esn->replay_window;
536 replay_esn->seq = seq;
537
538 if (unlikely(wrap > 0))
539 replay_esn->seq_hi++;
540 } else {
541 diff = replay_esn->seq - seq;
542
543 if (pos >= diff)
544 bitnr = (pos - diff) % replay_esn->replay_window;
545 else
546 bitnr = replay_esn->replay_window - (diff - pos);
547 }
548
549 nr = bitnr >> 5;
550 bitnr = bitnr & 0x1F;
551 replay_esn->bmp[nr] |= (1U << bitnr);
552
553 if (xfrm_aevent_is_on(xs_net(x)))
554 x->repl->notify(x, XFRM_REPLAY_UPDATE);
555 }
556
557 static struct xfrm_replay xfrm_replay_legacy = {
558 .advance = xfrm_replay_advance,
559 .check = xfrm_replay_check,
560 .recheck = xfrm_replay_check,
561 .notify = xfrm_replay_notify,
562 .overflow = xfrm_replay_overflow,
563 };
564
565 static struct xfrm_replay xfrm_replay_bmp = {
566 .advance = xfrm_replay_advance_bmp,
567 .check = xfrm_replay_check_bmp,
568 .recheck = xfrm_replay_check_bmp,
569 .notify = xfrm_replay_notify_bmp,
570 .overflow = xfrm_replay_overflow_bmp,
571 };
572
573 static struct xfrm_replay xfrm_replay_esn = {
574 .advance = xfrm_replay_advance_esn,
575 .check = xfrm_replay_check_esn,
576 .recheck = xfrm_replay_recheck_esn,
577 .notify = xfrm_replay_notify_esn,
578 .overflow = xfrm_replay_overflow_esn,
579 };
580
581 int xfrm_init_replay(struct xfrm_state *x)
582 {
583 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
584
585 if (replay_esn) {
586 if (replay_esn->replay_window >
587 replay_esn->bmp_len * sizeof(__u32) * 8)
588 return -EINVAL;
589
590 if (x->props.flags & XFRM_STATE_ESN) {
591 if (replay_esn->replay_window == 0)
592 return -EINVAL;
593 x->repl = &xfrm_replay_esn;
594 } else
595 x->repl = &xfrm_replay_bmp;
596 } else
597 x->repl = &xfrm_replay_legacy;
598
599 return 0;
600 }
601 EXPORT_SYMBOL(xfrm_init_replay);
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